Method of manufacturing a steering wheel

Abstract

A method of manufacturing a motor car steering wheel with an external shell made of carbon fibers begins with preparing a pile of sheet materials which is then hot molded to yield respective half-shells with a shape corresponding to that of respective halves of the steering wheel being manufactured. Next comes mechanical flattening of the front surfaces of the two half-shells, followed by mounting of the two half-shells above and under a steering wheel body formed by a metallic core covered by resin. The steering wheel body has lateral profile members which act as fixing supports for the two half-shells.

We claim:  
     
       1. A method of manufacturing a steering wheel with an external shell made of carbon fibers, which comprises: 
       preparing a pile of sheet materials;  
       hot molding the pile for obtaining respective half-shells with a shape corresponding to that of respective halves of the steering wheel being manufactured, said shape comprising a curved central part and two lateral fins;  
       mechanical flattening of exterior surfaces of the two half-shells by removing the lateral fins;  
       providing a steering wheel body with lateral profile members, each lateral profile member having two lateral flanges arranged at a side of the steering wheel body and an intermediate rib, said lateral profile members configured to mate with and support circumferentially extending edges of the curved central parts of the two half shells; and  
       mounting the two half-shells above and under the steering wheel body.  
     
     
       2. A method of manufacturing a steering wheel according to  claim 1 , wherein the mounting of the two half-shells comprises gluing an internal surface of the half-shells on an external surface of the lateral profile members, which is complementarily shaped. 
     
     
       3. A method of manufacturing a steering wheel according to  claim 1 , wherein said sheet materials comprise carbon fibers and glass fibers. 
     
     
       4. A method of manufacturing a steering wheel according to  claim 1 , wherein said sheet materials comprise carbon fibers and aramidic fibers. 
     
     
       5. A method of manufacturing a steering wheel according to  claim 1 , wherein said sheet materials comprise carbon fibers, glass fibers and aramidic fibers. 
     
     
       6. A method of manufacturing a steering wheel according to  claim 3 , wherein said fibers are impregnated by resin. 
     
     
       7. A method of manufacturing a steering wheel according to  claim 4 , wherein said fibers are impregnated by resin. 
     
     
       8. A method of manufacturing a steering wheel according to  claim 5 , wherein said fibers are impregnated by resin. 
     
     
       9. A method of manufacturing a steering wheel according to  claim 1 , wherein said hot molding is carried out at a temperature between 70° C. and 150° C. 
     
     
       10. A method of manufacturing a steering wheel according to  claim 1 , wherein said hot molding is carried out for a time between 1 and 3.5 minutes. 
     
     
       11. A method of manufacturing a steering wheel according to  claim 1 , wherein said hot molding is carried out at a pressure of at least 0.7 bar.